1. Field of the Invention
The invention relates to a substrate cleaning system, particularly to a wet cleaning treatment technique for applying to a semiconductor wafer and the like a wet cleaning treatment which is carried out in a pre-step process of a thin film forming process by a spattering, a CVD process and the like in a device fabricating process of a semiconductor, electronic devices and the like.
2. Related Art
For a method of applying a wet cleaning treatment to a semiconductor wafer and the like (hereinafter referred to simply as a wafer), a batch processing wet cleaning treatment has been conventionally a mainstream in which a plurality of wafers accommodated in a carrier cassette or a plurality of wafers without being accommodated in a carrier cassette are subsequently immersed by a transport unit and processed in a wet batch type cleaning solution bath comprised of a plurality of consecutively aligned cleaning solution baths. However, entering upon a sub-micron application age of recent semiconductor devices, a very high cleanliness required on its surface as the construction of such a semiconductor device is micro-fabricated and highly integrated. To satisfy the foregoing high cleanliness, a so called sheet-type wet cleaning treatment is developed and proposed wherein wet cleaning treatment is applied to a plurality of wafers one by one in a sealed cleaning room without being accommodated in a cassette.
In the sheet-type wet cleaning treatment, the wafers can be cleaned with a high precision in a high cleanliness atmosphere while particles are not re-stuck to the wafers, and hence this cleaning is simple and compact in construction and has an advantage that it can effectively cope with a large item small scale production.
Since cleaning equipment per se is installed in a clean room while it is kept in a high cleanliness at an atmosphere in both the conventional batch processing wet cleaning treatment and sheet-type wet cleaning treatment, an equipment body is opened in its floor section and wafer carry-in and carry-out sections thereof while booths in the equipment body are respectively opened so as to take precedence of workability.
However, with the construction of the conventional cleaning equipment, it is impossible to completely prevent particles from being re-stuck onto wafers after cleaning treatment, splash of cleaning solution and the like involved in applying a cleaning treatment to wafers, and adverse effects upon an operator caused by generations of dust from the wafers per se. Further, it is necessary to apply a corrosion resistance coating to an entire wall surface of the equipment body, leading to a problem of high fabricating cost.
The invention has been made in view of the problems of the foregoing cleaning equipment, and it is an object of the invention to provide a substrate cleaning system which is capable of cleaning wafers in a high cleanliness atmosphere with high accuracy taking advantage of the sheet-type wet cleaning treatment for applying a cleaning treatment to the wafers one by one in a sealed cleaning chamber without being accommodated in a cassette, and which is simple and compact in construction, and is excellent in cost performance.
To achieve the above object, the substrate cleaning system of the invention comprises a system body 1 capable of being sealed, a loading/unloading booth A comprising a substrate carry-in section Aa in which a plurality of wafers W are stocked on standby to be carried in before they are processed and a substrate carry-out section Ab in which a plurality of wafers W are stocked on standby to be carried out after they are processed, a processing booth C provided with at least one sheet-type substrate cleaning chamber 10 in which a plurality of wafers are cleaned by a plurality of cleaning solutions, and a robot booth B sandwiched between the processing booth C and the loading/unloading booth A and provided with a transport robot for transporting the wafers one by one, wherein the respective booths are partitioned by partition walls each having a required minimum cross sectional area.
In a preferred embodiment, the loading/unloading booth A and the robot booth B are respectively installed back and forth at both sides of the system body 1, the robot booth B is sandwiched between the loading/unloading booth A and the processing booth C, the loading/unloading booth A has openings 11, 12 which are openable to an operating space provided outside the system body.
With the loading/unloading booth A, the wafers to be stocked in the carry-in section Aa and carry-out section Ab are aligned horizontally with a given alignment pitch in a vertical direction, and clean air flowing inside the loading/unloading booth A is directed from the carry-in section Aa to the carry-out section Ab.
The transport robots 70 in the robot booth B are formed of a twin arm robot each provided with a pair of hand sections 70a, 70b movable vertically and horizontally, and one of the hand sections transports the wafers to which a cleaning treatment is not applied yet (hereinafter referred to as xe2x80x9cwafer before cleaning treatmentxe2x80x9d) while the other hand section transports the wafers to which a cleaning treatment was applied (hereinafter referred to as xe2x80x9cwafer after cleaning treatmentxe2x80x9d.
The corrosion resistance coating treatment is applied to the inner wall surface of the processing booth C a with vinyl chloride resin and oxidation resistance painting treatment is applied to the other wall side of the processing booth C. Further, the sheet-type substrate cleaning chamber 10 in the processing booth C is provided with a plurality of circular processing baths 85 to 88 which are aligned vertically, and comprises a chamber body 80 which moves vertically, and a substrate rotating unit 81 which is disposed concentrically with the chamber body 80 at the center and rotates a piece of wafer horizontally while supporting it horizontally, and wherein the wafers supported by the substrate rotating unit 81 and the circular processing baths 85 to 88 are positioned when the chamber body 80 moves up and down vertically. Further, the chamber body 80 is a sealed container provided with an openable substrate carry-in gate 90.
According to the invention, since the loading/unloading booth A, processing booth C and robot booth B are respectively installed in the system body which can be sealed, and the respective booths are partitioned by partition walls each having a required minimum sectional area, incoming and outgoing of air between the system body and the outside are restrained to a required minimum extent, so that the interior of the system body can be maintained in a high cleanliness atmosphere.
Since the system is of a sheet-type wet cleaning treatment for applying a cleaning treatment to wafers one by one, particles and the like are scarcely re-stuck to the wafers so that wafers can be processed with a high precision, and a cleaning space in the substrate cleaning chamber is rendered small and a quantity of cleaning solution is rendered small.
Since the system also employs a one chamber type for applying a cleaning treatment to the wafers one by one by a plurality of cleaning solutions, namely, all the cleaning treatments can be effected in one substrate cleaning chamber, the wafers are not carried in or out of the chamber in the cleaning steps so that the wafers do not contact an outside atmosphere, and hence they are not susceptible to a metallic contamination or influence of ion and oxygen and the like, and the construction of each substrate cleaning chamber can be simplified and small sized.
Since the loading/unloading booth A and the robot booth B are respectively installed back and forth at both sides of the system body 1, and the robot booth B is sandwiched between the loading/unloading booth A and the processing booth C, harmful gas or particles generated when cleaning treatment is effected in the processing booth are not leaked into an operating space outside the system body.
Further, since the wafers stocked in the carry-in section Aa and carry-out section Ab are aligned vertically in a horizontal state at a given alignment pitch, clean air flowing in the loading/unloading booth A is directed horizontally from the carry-out section Ab to carry-in section Aa and the transport robots 70 in the robot booth B are formed of a twin arm robot each provided with a pair of hand sections 70a, 70b wherein one of the hand sections transports the wafer before cleaning treatment while the other hand section transports the substrate after cleaning treatment, it is possible to effectively prevent particles and the like from being re-stuck to the wafers after cleaning treatment from the wafer before cleaning treatment.